It depends on when it breaks in pregnancy and if you are in a hospital setting. Or if there are any other problems. Generally i think its supposed to be 24hrs but it really depends on the circumstances.

it's not too long becasue since your water is the baby's amniotic flluid, it's crucial to his/her life. watiting too long will kill the baby. its best to get to a hospital and if you are in the hospital, they should monitor the baby's heartrate in case she/he's not coming and they need to preform an emergency c section

Ok, this is why I asked - I only heard after the fact that it was 24 hours. My water broke for my daughter at 7am on a Friday morning, and she wasn't born until 1am on Sunday. I was 36 weeks. I got to the hospital around 9am and they kept me there the whole time, but I wasn't progressing enough, as she couldn't fit through my pelvis eventhough she was small. So that's 42 hours!